Figure 7-11.--Block diagram of the collision alarm module.

Figure 7-11.--Block diagram of the collision alarm module.

Figure 7-11 is a block diagram of a collision alarm

Resistor R203 (not shown) is used in the circuit to

adjust the frequency to precisely 1000 Hz. Clockwise

module. Operation of the collision alarm contact maker

rotation of the pot will increase the frequency, while

will supply -10 volts dc to all stages in the circuit through

counterclockwise rotation will decrease the frequency.

relay K101. K101 will also apply control voltage to

operate the visual signal circuit and the amplifier

There are also two other transistors in the chemical

channel.

alarm circuit. These transistors are associated with the

general alarm and will be discussed later.

Resistor R107 (not shown) is a trimpot used in the

circuit to adjust the number of pulses in a group.

GENERAL ALARM.-- The general alarm

consists of a 400-cycle per second rectangular wave

Clockwise rotation of the pot will decrease the number

oscillator coupled through a gated transformer. A

of pulses, while counterclockwise rotation will increase

striking multi vibrator supplies current to a diode across

the number of pulses. Resistor R127 (not shown) is a

the gating winding of this transformer that produces the

trimpot used in the circuit to adjust the frequency to

decaying characteristics of a gong. A timing

exactly 1000 Hz. Clockwise rotation of the pot will

multivibrator and relay holds the operating relay in the

increase the frequency, while counterclockwise rotation

operating position for a period of 10 to 15 seconds after

will decrease the frequency.

the alarm contact maker is released. Figure 7-13 is a

block diagram of a general alarm module. Operation of

CHEMICAL ALARM.-- The chemical alarm is a

transistorized oscillator circuit that generates a

continuous 1000-Hz signal as long as power is applied

to the circuit. This circuit consists of a square wave

multi vibrator. Figure 7-12 is a block diagram of a

chemical alarm module. Operation of the chemical

alarm contact maker will supply -10 volts dc to the

circuit through relay K201. Relay K201 will also apply

control voltage to operate the visual signal circuit and

Figure 7-12.--Block diagram of the chemical alarm module.

the amplifier channel.

7-12