Understanding Form A, Form B and Form C Contact arrangements.

Understanding Form A, Form B and Form C Contact arrangements.

“Form A” is a Contact configuration term for relays. It refers to a Single Pole-Single Throw normally open contact. "1 Form A" means there is one Form A contact in the relay, "2 Form A" means there are two "Form A contacts" in the relay, so on and so forth.

Form A Normally Open is the most common configuration for relays. The relay acts as a switch and breaks the circuit. Then a small control voltage or current is applied to close the relay, therefore connecting the circuit.

Toward provides a wide range of contact forms and multi-channel relays, from Optically-coupled MOSFET Relays, Reed Relays, Multi-Channel Reed Relays to our six channel MEMS Switch. To search for Form A normally open relays in our fleet, please click the "MULTIPLE SEARCH" on the upper right of the page and choose the [CONTACT FORM] as you need. Or use the below form to tell us your need, and our professional team will contact you with the suggestion soon.

Toward offers a wide range of Form A Normally Open Relays, from Optically-coupled MOSFET Relays, Reed Relays, Multi-Channel Reed Relays to our six channel MEMS Switch. To search for Form A normally open relays in our fleet, please select your desired "Contact Form" in "multiple search." Or tell us your requirements through below form.

Form B refers to a normally closed Single Pole-Single Throw contact arrangement in a relay. This means that it stays in a closed (off) state without you driving the relay to operate. "1 Form B" means there is one "Form B contact," "2 Form B" means there are two "Form B contacts" in the relay, so on and so forth.

Form C refers to a Single Pole-Double Throw (SPDT) contact, which means that there is one common point connected to one normally open-end and another normally closed contact. "2 Form C" refers to two "Form C contacts," so on and so forth.

• 26 Series: Load Voltage 40V / Load Current 3.5A
• 28 Series: Load Voltage 40V / Load Current 4.5A
• 45 Series: Load Voltage 60V / Load Current 200mA
• 30 Series: Load Voltage 400V / Load Current 120mA
• 38 Series: Load Voltage 600V / Load Current 80mA
• 40 Series: Load Voltage 1500V / Load Current 45mA
• 58 Series: Load Voltage 1800V / Load Current 30mA

• SIP Series (Load Voltage 150V / Load Current 1.75A): 1 Form A (SPST, Normally Open), 1 From B (SPST, Normally Close)
• MSIP Series (Load Voltage 200V / Load Current 1.5A): 1 Form A (SPST, Normally Open), 2 Form A (SPDT, Normally Open)
• DIP Series (Load Voltage 100V/Load Current 1A): 1 Form A (SPST, Normally Open), 2 Form A (Normally Open), 1 Form B (SPST, Normally Close), 1 Form C (SPDT, Normally Open/Normally Close)
• VSIP Series(Load Voltage 230V/Load Current 1A) Switch vertically packaged: 1 Form A (SPST, Normally Open)
• VN Series (Load Voltage 150V/Load Current 1A) Switch vertically packaged with Multi-Channel: 1 Form A (SPST, Normally Open), 2 Form A (SPDT, Normally Open), 4 Form A (SP4T, Normally Open)
• BU Series (DC to 6GHz Load Voltage 210V/Load Current 1A): 1 Form A (SPST, Normally Open), 1 Form C (SPDT, Normally Open/Normally Close)

Mos Relays

SMD-4, 40V/2.5A Opto-MOS Relay

The 26 series is a SMD-4, load Voltage at 40V, load current up to 2.5 Amps, SPST normally open IC Solid State Relay (1 Form A).

SMD-6, 40V/4.5A Opto-MOS Relay

The 28 series is a SMD-6, load Voltage at 40V, load current up to 4.5 Amps, SPST normally open IC Solid State Relay (1 Form A).

SOP-4, 60V/200mA, Opto-MOS Relay

TOWARD RELAY’S AB45S is a load voltage 60V, load current 200mA SPST 1 Form A Normally open IC Solid State Relay.

SOP-4, 400V/100mA, Opto-MOS Relay

Our SOP-4 IC Solid State Relay is designed with a load voltage of 400V and capable of carrying a load current of 100mA incorporates a MOSFET along with a LED driver.

SMD-6, 600V/80mA, Opto-MOS Relay

This is a load voltage 600V, load current 80mA miniature single-pole normally open 1 Form A IC Solid State Relay.

SMD-6, 1500V/45mA, Opto-MOS Relay

This is a load voltage 1500V, load current 45mA SMD-6 IC Solid State Relay with a DIP-6 package.

SMD6-5,1800V/30mA,Opto-MOS Relay (SiC MOSFET)

Our 58 Series is a output solid-state relay, utilizing the SMD6-5 package (6.4mm*8.8mm), supports load voltages up to 1800V while carrying a current of 30mA.

Reed Relays

1 Form A, 10W/200V/1A Reed Relay

10W/200V/1A Reed Relay comes in 1 Form A contact arrangement, with load voltage at 200VDC and carry current at 1 Amps, nominal coil voltage is in choices of 5V, 12V, and 24V.

1 Form B, 10W/200V/1A Reed Relay

This is a load voltage 200V, carry current at 1 Amp Reed Relay in a 1 Form B contact arrangement, nominal coil voltage is in choices of 5V, 12V, and 24V.

10W/200V/1.5A 1 Form A Reed Relay

The 10W/200V/1.2A miniature Reed Relay features a 40% smaller footprint compared to standard SIP reed relays, making them the perfect fit for high-density test matrices.

10W/200V/1.2A 2 Form A Miniature Reed Relay

The MSIP-2A Series from Toward is a 2 Form A (DPST-NO) miniature reed relay rated for 200V and 1.2A

10W/200V/1A Reed Relay

This Reed Relay comes in a 1 Form A normally open contact arrangement with a breakdown voltage at 200VDC and carries current at 1 Amp.

2 Form A 10W/ 200V / 1A Multi-channel Reed Relay

Multi-channel Reed Relay with 2 Form A normally open contacts features a breakdown voltage at 200VDC and carries current at 1 Amp.

10W/200V/1A, 1 Form B Reed Relay

The DIP-1B Series is a 1 Form B reed relay from Toward supports 200VDC breakdown voltage and 1A carry current, with coil voltage options of 5VDC, 12VDC, and 24VDC.

3W/200V/0.5A, 1 Form C Reed Relay

This Form C Reed Relay has a breakdown voltage at 200VDC and carries current at 1 Amp.

1 Form A 10W / 200V / 1A Reed Relay

The 1 Form A 10W Reed Relay designed with a unique tilted configuration to maximize PCB space efficiency, supports a load voltage of 200VDC and a carrying current of 0.5 Amp.

2 Form A 10W / 200V / 1A Reed Relay

The 2 Form A Vertical Miniature Reed Relay, with its unique standing design tailored to conserve board space, is widely acclaimed in Taiwan's semiconductor testing industry.

4 Form A 10W / 200V / 1A Reed Relay

This is a vertical miniature reed relay unique in its standing design to save board space. It is designed in 4 Form A, normally opened contact arrangement.

10W/ 210V/ 1A High Frequency Reed Relay, 6GHz, 1 Form A

High Frequency Reed Relay that can switch signals up to 6.5GHz with a breakdown voltage at 210VDC and carry currents up at 1 Amp. 3W/210V/1A Reed Relay is designed with a Form A normally opened contact arrangement.

3W/ 200V/ 0.2A High Frequency Reed Relay, 6GHz, 1 Form C

High Frequency Reed Relay can switch signals up to 6.5GHz with breakdown voltage at 200VDC and carry current at 0.2 Amp. 3W/200V/0.2A Reed Relay is designed with a Form C contact arrangement.